• Journal of the Korean Society for Aviation and Aeronautics
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• v.26 no.3
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• pp.40-47
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• 2018

Reducing aircraft speed is the important task in the Rejected Takeoff and/or landing process. It is known that the effect of the Speedbrake is most important factor during the rejected takeoff maneuver in particular near V1 on the critical field length runway. The B747 designer created Automatic Speedbrake Control System to relieve pilot workload, improves brake operation and ensures proper Speedbrake operation for rejected take off. However, those who make the Rejected Takeoff procedure ignored the Automatic function and made it does all manual operations. This lets procedures difficult, complicated, and a cause of confusion and pilot error. This study was conducted to commentary the mechanism and function of the Automatic Speedbrake Control System of B747-8 and to propose appropriate B747-8 Rejected Take off procedures for its function to reduce the workload of pilots and contribute to reduce the possibility of pilot error during Rejected Takeoff.

• Journal of the Korean Society for Railway
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• v.12 no.1
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• pp.72-80
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• 2009

The tribiological characteristics such as friction coefficient, friction stability, wear rate and braking temperature between various types of metallic friction materials and heat resistant steel disk, were investigated by using lab-scale dynamometer. Friction materials for high speed train have higher friction coefficient and friction stability as compared to aircraft friction materials even though friction materials for high speed train have lower wear rate. In addition. Cu-matrix friction materials have higher temperature increase rate than Fe-matrix friction materials. All friction surfaces have Fe-base oxide layer after completing test.

• Composites Research
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• v.27 no.4
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• pp.123-129
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• 2014

Ceramic matrix composites (CMCs) consist of such reinforcements as carbides, nitrides, borides and oxides, which have high melting points, low density, high modulus and high strength, for the purpose of increasing toughness. These materials are used for heat shielding systems for aerospace vehicles, high-temperature gas turbine combustion chambers, turbine blades, stator vane parts, etc. Oxide CMCs are used for the components of burner and flame holder and the high-temperature gas duct. CMCs are also applied to brake disks, which are subjected to severe thermal shock, and slide bearing parts under heavy loads. The research and development of the CMC are progressed for the strategic purpose in defense and energy industry; for instance, for aerospace applications in the U.S., and for hyper-speed aircraft, gas turbines, and atomic fissions in U.S., Japan, and Europe.

• Journal of Advanced Navigation Technology
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• v.23 no.1
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• pp.44-54
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• 2019

In many countries, there are needs of new transportations to replace ground congestions due to growing number of cars. In addition, the increase in the number of cars held by economic growth will further increase traffic congestion in the future. To overcome this problem, many researches have been performed for personal air vehicle (PAV). In this study, the wing loading and the power-to-weight ratio that are major design parameters for the sizing of roadable PAVs were calculated for different kinds of airfoil and engine types. I.e., in the sizing process, the study was conducted to determine the design point using the graphs of wing loading, power-to-weight ratio, brake horse power, and fuel efficiency for the given mission profiles considering domestic environments and the FAR PART 23 which is the GA class aircraft certification standard. As a result of sizing, using diesel engine require high maximum take-off weight, wing area, and power compared to gasoline engine due to more engine weight.